We have carried out a survey of compact star clusters ( apparent size \lesssim 3″ ) in the southwest part of the M31 galaxy , based on the high-resolution Suprime-Cam images ( 17.5 \arcmin \times 28.5 \arcmin ) , covering \sim 15 % of the deprojected galaxy disk area .
The UBVRI photometry of 285 cluster candidates ( V \lesssim 20.5 mag ) was performed using frames of the Local Group Galaxies Survey .
The final sample , containing 238 high probability star cluster candidates ( typical half-light radius r _ { h } \sim 1.5 pc ) , was selected by specifying a lower limit of r _ { h } \gtrsim 0.15 \arcsec ( \gtrsim 0.6 { pc } ) .
We derived cluster parameters based on the photometric data and multiband images by employing simple stellar population models .
The clusters have a wide range of ages from \sim 5 Myr ( young objects associated with 24 \mu m and/or H \alpha emission ) to \sim 10 Gyr ( globular cluster candidates ) , and possess mass in a range of 3.0 \lesssim \log ( m / m _ { \sun } ) \lesssim 4.3 peaking at m \sim 4000 m _ { \sun } .
Typical age of these intermediate-mass clusters is in the range of 30 { Myr } \lesssim t \lesssim 3 Gyr , with a prominent peak at \sim 70 Myr .
These findings suggest a rich intermediate-mass star cluster population in M31 , which appears to be scarce in the Milky Way galaxy .